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From: Phil Sutter <phil@nwl.cc>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: netfilter-devel@vger.kernel.org
Subject: [nft PATCH 4/4] netlink: Avoid potential NULL-pointer deref in netlink_gen_payload_stmt()
Date: Mon, 20 Jan 2020 17:25:40 +0100	[thread overview]
Message-ID: <20200120162540.9699-5-phil@nwl.cc> (raw)
In-Reply-To: <20200120162540.9699-1-phil@nwl.cc>

With payload_needs_l4csum_update_pseudohdr() unconditionally
dereferencing passed 'desc' parameter and a previous check for it to be
non-NULL, make sure to call the function only if input is sane.

Fixes: 68de70f2b3fc6 ("netlink_linearize: fix IPv6 layer 4 checksum mangling")
Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 src/netlink_linearize.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index 498326d0087a1..cb1b7fe1748b2 100644
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -941,7 +941,7 @@ static void netlink_gen_payload_stmt(struct netlink_linearize_ctx *ctx,
 		nftnl_expr_set_u32(nle, NFTNL_EXPR_PAYLOAD_CSUM_OFFSET,
 				   csum_off / BITS_PER_BYTE);
 	}
-	if (expr->payload.base == PROTO_BASE_NETWORK_HDR &&
+	if (expr->payload.base == PROTO_BASE_NETWORK_HDR && desc &&
 	    payload_needs_l4csum_update_pseudohdr(expr, desc))
 		nftnl_expr_set_u32(nle, NFTNL_EXPR_PAYLOAD_FLAGS,
 				   NFT_PAYLOAD_L4CSUM_PSEUDOHDR);
-- 
2.24.1


  parent reply	other threads:[~2020-01-20 16:25 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-20 16:25 [nft PATCH 0/4] Fixes for a recent covscan run Phil Sutter
2020-01-20 16:25 ` [nft PATCH 1/4] netlink: Fix leak in unterminated string deserializer Phil Sutter
2020-01-21 12:55   ` Pablo Neira Ayuso
2020-01-20 16:25 ` [nft PATCH 2/4] netlink: Fix leaks in netlink_parse_cmp() Phil Sutter
2020-01-21 12:55   ` Pablo Neira Ayuso
2020-01-20 16:25 ` [nft PATCH 3/4] segtree: Fix for potential NULL-pointer deref in ei_insert() Phil Sutter
2020-01-21 12:56   ` Pablo Neira Ayuso
2020-01-27 13:24     ` Phil Sutter
2020-02-21 22:07       ` Phil Sutter
2020-01-20 16:25 ` Phil Sutter [this message]
2020-01-21 12:57   ` [nft PATCH 4/4] netlink: Avoid potential NULL-pointer deref in netlink_gen_payload_stmt() Pablo Neira Ayuso

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